This invention relates to a seal for a lubricated track on a track-laying vehicle. More particularly, this invention relates to a two-piece seal arrangement, one piece of which serves to engage the surfaces of a track link assembly so as to seal lubricant in the assembly and prevent the introduction of dirt and other foreign matter to the lubricant areas of the assembly.
In a conventional type of track linkage, there are provided inner and outer link portions that are connected at a common end and through which a pin extends. The outer link portion normally has an annular recess facing the inner link portion. A track bushing extends through and is connected to the inner link portion and normally has its end closing the recess of the outer link. The track bushing oscillates with the inner link portion and relative to the pin which is fixed to the outer link portion. Lubricant is fed through the center of the pin and suitable orifices extend to the area between the pin and the bushing for providing lubricant between those surfaces. The seal assembly fits in the recess and seals the recess against leakage of the lubricant and also prevents dirt and other foreign matter from entering into the areas of lubrication.
In the normal design of the seal assembly, there is provided a main seal ring that has a lip which engages the end of the track bushing and serves to seal that end against lubricant leakage. The main seal ring is held in its correct position by a load ring that fits next to the seal ring and walls of the recess and in effect, holds the lip in its proper position. In this arrangement, the track bushing oscillates with respect to the lip on the seal assembly.
The problem with the conventional-type seal is that often, the lip will become worn or will cut an annular groove in the end of the track bushing which eventually permits leakage of the lubricant or passage of the foreign materials into the lubricated areas.